Safety and Feasibility of Low-Dose Apatinib Combined with S-1 as the Second-Line Therapy or Beyond in Chinese Patients with Pulmonary and Hepatic Metastasis of Nasopharyngeal Carcinoma

Introduction: The purpose of this study was to analyze the safety and feasibility of low-dose apatinib combined with S-1 as a second-line therapy or beyond in Chinese patients with pulmonary and/or hepatic metastases of nasopharyngeal carcinoma (NPC). Methods: Forty-one Chinese NPC patients with pulmonary and hepatic metastases were treated with low-dose apatinib plus S-1. The S-1 dose was determined according to each patient's body surface area (BSA): 40 mg twice a day for BSA <1.25 m2; 50 mg twice a day for 1.25 m2≤BSA <1.5 m2; and 60 mg twice a day for BSA ≥1.5 m2. S-1 was received for 14 days, after stopping for 7 days, given 3 weeks apart. Apatinib, 125 mg was orally administered daily on days 1 through 28 of each 4-week cycle. If the toxicity was not tolerable, the dose of apatinib was reduced to 125 mg every other day. Results: Treatment efficacy was evaluated in all 41 patients after four courses of chemotherapy. The objective response rate was 34.1%, and the disease control rate was 80.4%. The median progression-free survival was 9.7 months (95% confidence interval, 6.2-13.8 months), and the median overall survival was 22.1 months (95% confidence interval, 15.1-28.9 months). The 2-year survival rate was 41.5%. The most common toxicities included loss of appetite in 39.0% of patients, dyslipidemia in 34.1%, hypertension in 31.7%, myelosuppression in 24.4%, fatigue in 21.9%, and hand-foot syndrome in 17.1%. Seven patients received dose adjustment of apatinib due to side effects. Conclusion: In patients with pulmonary and/or hepatic metastases of NPC, low-dose apatinib plus S-1 yielded an excellent survival benefit, and the toxicities were mild and tolerable.